Variable sound system for audio devices

ABSTRACT

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of electronic device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/576,246, filed Sep. 19, 2019, which is a continuation of U.S. patentapplication Ser. No. 16/267,182, filed Feb. 4, 2019, which is acontinuation of U.S. patent application Ser. No. 15/617,862, filed Jun.8, 2017, now U.S. Pat. No. 10,195,452, issued on Feb. 5, 2019, which isa continuation of U.S. patent application Ser. No. 14/526,108, filedOct. 28, 2014, now U.S. Pat. No. 9,713,728, which claims the benefit ofand priority to U.S. Provisional Patent Application No. 61/897,136,filed Oct. 29, 2013, and titled “Variable Sound System for MedicalDevices,” each of which is incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The disclosed subject matter pertains to the area of electronic devices.

BACKGROUND INFORMATION

The use of field-deployed medical devices, such as portabledefibrillators, is achieving widespread acceptance. Such devices aredesigned to be used in high-stress environments by people who may not bewell trained. Thus, the medical devices commonly provide audible cues tothe user to guide the use of the medical device. However, such medicaldevices may be deployed in greatly disparate noise environments rangingfrom very quiet, such as an office setting, to very loud, such as arailroad station. Thus, the audible cues must compete with drasticallydifferent ambient sounds that interfere with the intelligibility of theaudible cues.

Portable devices are also constrained by size, weight, and powerlimitations.

SUMMARY OF EMBODIMENTS

Disclosed is a system capable of self-adjusting both sound level andspectral content to improve audibility and intelligibility of medicaldevice audible cues. Audible cues are stored as sound files. Ambientnoise is detected, and the output of the audible cues is altered basedon the ambient noise. Various embodiments include processed sound filesthat are more robust in noisy environments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a scene where an external defibrillator is usedto save the life of a person.

FIG. 2 is a functional block diagram generally illustrating corecomponents of one basic embodiment.

FIG. 3 is a functional block diagram illustrating components of a firstalternative embodiment that improves on the basic embodiment of FIG. 1.

FIG. 4 is a functional block diagram illustrating components of a secondalternative embodiment that improves on the first alternative embodimentof FIG. 3.

FIG. 5 a functional block diagram illustrating components of a thirdalternative embodiment that improves on the first and second alternativeembodiments of FIGS. 3 and 4.

FIG. 6 is a sample spectrogram illustrating a 440 Hz pure sine tone,representing an audible cue.

FIG. 7 is a spectrogram illustrating a 400 Hz masker signal.

FIG. 8 is a sample spectrogram revealing that when presented together,the 400 Hz masking sound dominates the 440 Hz audible cue.

FIG. 9 is a sample spectrogram showing an audible cue processed toinclude harmonics of the audible cue.

FIG. 10 is a sample spectrogram showing the altered audible cue of FIG.9 in combination with the masker signal shown in FIG. 8.

FIG. 11 is a sample spectrogram showing the altered audible cue of FIG.9 in combination with a masker signal having harmonics.

FIG. 12 is a sample spectrogram illustrating an audible cue altered inaccordance with characteristics of the human auditory system.

FIG. 13 is a sample spectrogram illustrating the critical band(described below) altered audible cue of FIG. 12 combined with themasking signal of FIG. 8.

FIG. 14 is a sample spectrogram illustrating the critical band alteredaudible cue of FIG. 12 combined with the masking signal havingharmonics.

DETAILED DESCRIPTION OF EMBODIMENTS

Generally described, embodiments are directed at discovering informationabout an ambient sound environment, such as sound level, or spectralcontent or both, and exploiting psycho-acoustic principles of the humanauditory system to enhance the ability to distinguish intended audiblecues from ambient noise. Specific embodiments exploit masking andcritical bands in the basilar membrane. Combining a measurement of theambient sound environment and a psycho-acoustically driven knowledgebase of the spectrum, a sound source is chosen or modified as necessaryto improve resistance to auditory masking, thereby improving theaudibility of alerts and alarms, and intelligibility of voice prompts.Although particularly applicable to the area of portable medicaldevices, the disclosed subject matter has applicability to many otherareas, such as the automotive industry, or the like.

FIG. 1 is a diagram of a defibrillation scene. A person 82 is lyingsupine. Person 82 could be a patient in a hospital, or someone foundunconscious and turned on his or her back. Person 82 is experiencing acondition in their heart 85, which could be Ventricular Fibrillation(VF).

A portable external defibrillator 100 has been brought close to person82. At least two defibrillation electrodes 104, 108 are usually providedwith external defibrillator 100. Electrodes 104, 108 are coupled withexternal defibrillator 100 via respective electrode leads 105, 109. Arescuer (not shown) has attached electrodes 104, 108 to the skin ofperson 82. Defibrillator 100 is administering, via electrodes 104, 108,a brief, strong electric pulse 111 through the body of person 82. Pulse111, also known as a defibrillation shock, goes also through heart 85,in an attempt to restart it, for saving the life of person 82.Defibrillator 100 can be one of different types, each with differentsets of features and capabilities. The set of capabilities ofdefibrillator 100 is determined by planning who would use it, and whattraining they would be likely to have.

In use, defibrillator 100 provides audible cues to inform the rescuer ofthe steps to properly operate defibrillator 100. However, thedefibrillation scene may occur in any one of many different environmentshaving greatly divergent audible characteristics. In other words, thedefibrillation scene may occur in a relatively quiet indoor environment,or it may occur in a relatively loud outdoor environment, or anything inbetween. Operating in various noise environments poses problems forselecting the appropriate format to output the audible cues. In loudenvironments, the audible cues can be difficult to hear if too quiet. Inquiet environments, the audible cues can be harsh on the ear and evenquasi painful if too loud. Either case (quiet or loud environments) bothresult in degradation in speech intelligibility under the foregoingconditions. Disclosed are embodiments that enable the defibrillator 100to automatically adjust the sound output of the audible cues based onthe ambient noise environment.

Generally stated, when two sounds are closely related in time andfrequency such that they are within a critical band of each other, thesound with the lower sound level will be masked by the one with thehigher sound level. This phenomenon is illustrated with reference to thesample spectrograms of FIGS. 6-8. In the spectrograms, the “X” axisdenotes time; 0 to 10 seconds. The “Y” axis represents frequency; 0 to4000 Hz. Sound levels are represented by brightness on the spectrogram;brighter is higher sound level, darker is lower sound level. Forsimplicity of discussion, simple sounds will be presented. However, theconcepts extend equally to complex sounds including music and speech.

Referring briefly to FIG. 6, illustrated is a sample spectrogram showinga 440 Hz pure sine tone. This tone represents an audible cue (e.g., analert) to be communicated to a user of a medical device. FIG. 7 is aspectrogram illustrating a 400 Hz masker signal. The masker signal willbe the interfering ambient sound. FIG. 8 is a sample spectrogramrevealing that when presented together, the 400 Hz masking sounddominates the 440 Hz audible cue. In this situation, the 440 Hz audiblecue will not be audible over the masker signal. The embodiments shown inFIGS. 2 5 seek to ameliorate this situation and enhance intelligibilityof audible cues output by a medical device.

FIG. 2 is a functional block diagram generally illustrating componentsof one basic embodiment. In this basic embodiment, a system 200 isimplemented in a medical device and includes a microphone 202 to recordthe ambient noise being experienced in the environment and a library 201of sound files which each represent audible cues. Each audible cue maybe, in one implementation, a voice prompt or instruction for operatingthe medical device. In accordance with this embodiment, each sound fileis processed to enhance intelligibility in loud environments. Morespecifically, the sound files may be processed to enhance harmonicsignals of each audible cue, which serves to enhance the intelligibilityof the audible cue, especially in louder environments. However, suchprocessing may result in an audible cue which sounds somewhat harsh inquiet environments. Thus, it is desirable to output the audible cues ata volume that does not irritate the operator's hearing. Illustrativeprocessing methods are illustrated in FIGS. 9-14 and described below.

The sound recorded using the microphone 202 is conditioned using signalconditioner 204 and converted from an analog signal to a digital signalusing ADC 206. A sound level calculation component 208 then detects thesound level (e.g, volume) of the noise in the ambient environment. Usingthe detected sound level, a gain adjustment is applied to an amplifier212 thus adjusting the sound level of audible cues such that it isappropriate for the current environment.

In various implementations, the gain adjustment 210 could be either ananalog or digital control, with the latter depicted in FIG. 2. Whileoffering intelligent adjustment of the sound level, this version offersbasic improvement in resistance to auditory masking by ambient sounds.

FIG. 3 is a functional block diagram illustrating components of a firstalternative embodiment 300 that improves on the basic embodiment ofFIG. 1. Generally stated, components shown in FIG. 3 operate in the samemanner as similarly-labeled components shown in FIG. 2. However, thesound files in the sound library 301 of the first alternative embodimentare somewhat less processed than those in the sound library 201 of thebasic embodiment. Accordingly, the audible cues sound somewhat lessharsh in quiet environments at the expense of some loss inintelligibility in more noisy environments.

The first alternative embodiment operates largely in a similar manner asthe basic embodiment described above. Thus, the sound level of theambient noise of the environment is determined using a microphone 202and sound level calculation component 208. However, the firstalternative embodiment includes a harmonic processor 312 to addharmonically related frequency content to the audible cue to enhanceintelligibility at higher sound levels. In other words, when the soundlevel calculation determines that the medical device is operating in alouder ambient sound level, the gain of the amplifier is increased toraise the sound level of the audible cue. In addition, the harmonicprocessor 312 dynamically alters the sound files to include harmonicsthat enhance the intelligibility of the audible cues in noisyenvironments. Accordingly, the audible cues sound less harsh in quietenvironments where masking is less of a problem, but harshness is added(e.g., via third and fifth harmonics) to enhance intelligibility in anoisy environment.

As can be seen, the first alternative embodiment 300 produces more soundlevel when needed and also introduces harmonically-related spectralcontent to the output sound to enhance intelligibility at higher soundlevels. The first alternative embodiment 300 improves greatly on thebasic embodiment 200 for audibility in ambient noise.

FIG. 4 is a functional block diagram illustrating components of a secondalternative embodiment 400 that improves on the first alternativeembodiment of FIG. 3. As above, components shown in FIG. 4 operate inthe same manner as similarly-labeled components shown in FIGS. 2 and 3.However, the sound library 401 of the second alternative embodimentincludes sound files that are more processed to enhancenoisy-environment intelligibility (similar to the sound files used inthe basic embodiment) and sound files that are less processed (similarto the sound files used in the first alternative embodiment).Accordingly, each of the audible cues may have at least two (butpossibly more) corresponding sound files; at least one which soundsbetter in quieter environments and at least another that sounds betterin louder environments. Of course, there may be certain audible cues forwhich alternative sound files are not necessary.

In accordance with this embodiment, a sound level spectrum knowledgebase 410 is included which stores information about the spectralcharacteristics of typical maskers (i.e, competing noises which may maskthe audible cues) in particular noise environments. In other words,based on prior evaluations and analysis, this embodiment incorporates apriori knowledge regarding particular noise contributors in variousdifferent ambient environments. In this manner, a basic psycho-acousticenhancement processor (PAEP) 412 receives sound level information fromthe sound level calculation component 208 with an estimate of anappropriate gain that should be applied to a sound file based on thecurrent ambient environment (via gain estimator 414).

The PAEP 412 uses the measurement of ambient sound level in combinationwith the knowledge base 410 of environmental noise levels. Based on (atleast) those two inputs, the PAEP 412 determines which one of theseveral pre-processed sounds within sound library 401 best fit theambient situation. Gain to the amplifier 212 may also be adjusted forenhanced use of the chosen pre-processed sound. The pre-processed soundswithin library 401 have their spectral content adjusted based on one ofmany possible psycho-acoustic formulae for determining critical bandfrequencies of the basilar membrane. The spectral content of eachspecific sound is pre-processed to correspond with the various ambientsound level situations in the knowledge base 410.

FIG. 5 a functional block diagram illustrating components of a thirdalternative embodiment 500 that improves on the first and secondalternative embodiments of FIGS. 3 and 4. As above, components shown inFIG. 5 operate in the same manner as similarly-labeled components shownin FIGS. 2, 3 and 4. However, the sound library 501 of the thirdalternative embodiment may include sound files that are less processedto enhance noisy-environment intelligibility (similar to the sound filesused in the first alternative embodiment). The sound library 501 of thethird alternative embodiment may, but need not, also include sound filesthat are more processed (similar to the sound files used in the basicembodiment) for noisy-environment intelligibility.

The third alternative embodiment 500 includes a microphone 202 andancillary components to detect both sound level (i.e., sound levelcalculation component 208) and sound spectrum (i.e., sound spectrumanalysis component 508) of the ambient environment. Measurements ofthose two parameters are used to create estimates of predicted auditorymasking of the device sounds, via a spectrum enhancement estimationcomponent 510. A psycho-acoustic model of changes to the source soundspectrum emerges in real-time which may be used to make the sourcesounds more resistant to masking in the presence of potentially maskingsounds of the ambient environment. In this embodiment, an advanced PAEP512 predicts necessary changes to both sound level and spectral contentdynamically to enhance the sound output of the medical device for agiven environment.

In most embodiments, a hold function (not shown) should be used toprevent changes to the sensed ambient sound level and adjustments to thesound output during the period when the device is itself generatingsound (e.g., while playing an audible cue). This avoids makinginappropriate adjustments based on the device contribution to theambient environment.

Sample spectrograms will now be presented to help illustrate theoperation of the above-described embodiments. In particular, the samplespectrograms shown in FIGS. 9-14 provide guidance regarding theprocessing of sound files for use in the embodiments illustrated inFIGS. 2-5 and described above. As with FIGS. 6-8, the “X” axis denotestime; 0 to 10 seconds. The “Y” axis represents frequency; 0 to 4000 Hz.Sound levels are represented by brightness on the spectrogram; brighteris higher sound level, darker is lower sound level.

FIG. 9 is a sample spectrogram showing an audible cue processed toinclude harmonics of the audible cue. Altering the sound spectrum of theaudible cue such that energy is redistributed to the harmonics createsredundancies in non-overlapping auditory critical bands.

FIG. 10 is a sample spectrogram showing the altered audible cue of FIG.9 in combination with the masker signal shown in FIG. 8. As illustrated,when the 400 Hz single-frequency masker signal of FIG. 8 is presentedwith the altered audible cue of FIG. 9, the 400 Hz masker dominates thefundamental of the altered alert sound, but does not mask the higherharmonics. Thus, the altered alert audible cue is more robust to maskingby a single frequency sound.

FIG. 11 is a sample spectrogram showing the altered audible cue of FIG.9 in combination with a masker signal having harmonics. As shown, if thealtered audible cue may still be at risk of being hard to hear or eveninaudible in the same environment as the masker signal with harmoniccontent. It will be appreciated that this depends on proximity of themasking sound harmonics to the altered audible cue harmonics and if theyare both within a critical bandwidth of each other.

FIG. 12 is a sample spectrogram illustrating an audible cue altered inaccordance with characteristics of the human auditory system. Morespecifically, the adjustments to the audible cue are based on thepsycho-acoustic concept of a Critical Bandwidth (“CB”) that forms on thebasilar membrane when stimulated. The basilar membrane is located withinthe cochlea in the inner ear. Generally stated, the critical bandwidthis the band of audio frequencies within which a second tone willinterfere with the perception of a first tone by auditory masking. Onesuch estimation of the critical bandwidth is presented below:

CB=25+75[1+1.4 (freq/1000){circumflex over ( )}2] 0.69 Hz*

*Zwicker, Eberhard, Journal of Acoustical Society of America, November1980

-   -   (This formula is but one example of many different        equally-applicable formulae, as will be apparent to those        skilled in the art.)

FIG. 13 is a sample spectrogram illustrating the CB altered audible cueof FIG. 12 combined with the masking signal of FIG. 8. As is evidentfrom FIG. 13, the CB altered audible cue is extremely robust to singlefrequency masking.

FIG. 14 is a sample spectrogram illustrating the CB altered audible cueof FIG. 12 combined with the masking signal having harmonics. As isevident from FIG. 14, even when presented with a masking soundcontaining harmonic content, the CB altered audible cue remains audibleas it is stimulating non-overlapping CBs of the basilar membrane and thespectral content is spread to avoid the harmonics of maskers.

In this description, numerous details have been set forth in order toprovide a thorough understanding. In other instances, well-knownfeatures have not been described in detail in order to not obscureunnecessarily the description.

A person skilled in the art will be able to implement these additionalembodiments in view of this description, which is to be taken as awhole. The specific embodiments disclosed and illustrated herein are notto be considered in a limiting sense. Indeed, it should be readilyapparent to those skilled in the art that what is described herein maybe modified in numerous ways. Such ways can include equivalents to whatis described herein.

For example, in another embodiment for use in cars, trains, buses,planes, or other noisy environments in which audio announcements aremade, a system may include a microphone configured to capture ambientnoise; a sound library including a plurality of sound files, each soundfile corresponding to an audible cue; an amplifier coupled to a speaker,the amplifier having a selectable gain and being configured to outputeach of the plurality of sound files over the speaker; a sound leveldetection component coupled to the microphone and configured to detect asound level of the ambient noise; a sound spectrum detection componentcoupled to the microphone and configured to detect spectrumcharacteristics of the ambient noise; a sound spectrum analysiscomponent coupled to the sound spectrum detection component and beingconfigured to provide an estimate of an amount of gain to apply to tileamplifier based on an analysis of the spectral characteristics of theambient noise; and a sound altering component configured to alter theselectable gain of tile amplifier based on the sound level of theambient noise in conjunction with the estimate, or to alter harmoniccontent of the sound files based on the spectral characteristics of theambient noise, or both.

In addition, various embodiments may be practiced in combination withother systems or embodiments. The following claims define certaincombinations and subcombinations of elements, features, steps, and/orfunctions, which are regarded as novel and non-obvious. Additionalclaims for other combinations and subcombinations may be presented inthis or a related document

1-13. (canceled)
 14. A vehicle, comprising: a microphone configured todetect an ambient sound; a speaker configured to output an alteredaudible cue; and a processor configured to: determine that a volume ofthe ambient sound is greater than a threshold; based on determining thatthe volume of the ambient sound is greater than the threshold: identifyan audible cue comprising an instruction for operating the vehicle;determine a critical band of the audible cue, the critical band beingnon-overlapping with a frequency band of the ambient sound; generate thealtered audible cue by adding a signal associated with the critical bandto the audible cue; and cause the speaker to output the altered audiblecue.
 15. The vehicle of claim 14, further comprising: an amplifiercoupled to the speaker and configured to apply a gain to the alteredaudible cue, wherein the processor is further configured to: adjust thegain of the amplifier based on the volume of the ambient sound.
 16. Thevehicle of claim 14, further comprising: a sound library storing theaudible cue, wherein identifying the audible cue comprises accessing theaudible cue in the sound library.
 17. The vehicle of claim 14, whereinthe ambient sound comprises harmonics and the critical band isnon-overlapping with the harmonics.
 18. A device, comprising: amicrophone configured to detect a first sound, the first sound being anambient sound; a speaker configured to output a second sound; and aprocessor configured to: identify first data indicative of a thirdsound; generate second data indicative of a fourth sound comprising acritical band of the third sound, the critical band beingnon-overlapping with a frequency band of the first sound; cause thespeaker to output the second sound based on the first data and thesecond data.
 19. The device of claim 18, wherein the processor isfurther configured to determine that a sound level of the first sound isgreater than a threshold, and wherein the processor is configured tocause the speaker to output the second sound based on determining thatthe sound level of the first sound is greater than the threshold. 20.The device of claim 18, further comprising: a sound library storing thefirst data, wherein identifying the first data comprises accessing thefirst data in the sound library.
 21. The device of claim 18, wherein thethird sound comprises a voice prompt or an instruction for operating thedevice.
 22. The device of claim 18, further comprising: an amplifiercoupled to the speaker and configured to apply a gain to the secondsound, wherein the processor is further configured to: adjust the gainof the amplifier based on a sound level of the first sound.
 23. Thedevice of claim 22, wherein the processor is further configured toadjust the gain of the amplifier based on a spectrum of the first sound.24. The device of claim 18, wherein the microphone is further configuredto detect a fifth sound, and wherein the processor is further configuredto: determine that a sound level of the fifth sound is below athreshold; and based on determining that the sound level of the fifthsound is below the threshold, causing the speaker to output the thirdsound based on the first data.
 25. The device of claim 18, wherein thefirst sound comprises harmonics of the frequency band and the criticalband is non-overlapping with the harmonics of the frequency band.
 26. Amethod, comprising: detecting a first sound that comprises an ambientsound; determining data indicative of a second sound that comprises acritical band of an audible cue, the critical band being non-overlappingwith a frequency band of the first sound; and outputting the secondsound.
 27. The method of claim 26, further comprising: determining thata sound level of the first sound is greater than a threshold, whereinoutputting the second sound is further based on determining that thesound level of the first sound is greater than the threshold.
 28. Themethod of claim 26, further comprising retrieving data indicative of theaudible cue from a sound library.
 29. The method of claim 26, whereinthe audible cue comprises a voice prompt or an instruction for operatinga device.
 30. The method of claim 26, further comprising: adjusting again of an amplifier based on a sound level of the first sound, whereinoutputting the second sound is further based on the gain of theamplifier.
 31. The method of claim 30, further comprising: adjusting thegain of the amplifier based on a spectrum of the first sound.
 32. Themethod of claim 26, further comprising: detecting a third sound;determining that a sound level of the third sound is below a threshold;and based on determining that the sound level of the third sound isbelow the threshold, outputting a fourth sound based on the audible cuewithout the critical band.
 33. The method of claim 26, wherein the firstsound comprises harmonics of the frequency band and the critical band isnon-overlapping with the harmonics of the frequency band.